I have an all black trailer /with metal walls inside and little rooms for actors. (trailer in good shape will need new tires) electrical run through out with exit signs. It has stairs where you enter like the one shown below. I can send pics if interested. Or if you want a custom trailer haunt built email me and lets get this project rolling. We moved to a new spot and dont have space for it anymore. We used it as an old time sideshow add on.

I am going to take pics of the trailer tomorrow (inside and outside). Will post them here with measurements. Trailer is stored in a lot in Chicago IL. Trailer in good condition but it does need new tires.
Thanks everyone for their interest.